Recently, broadcasting service having High Definition (HD) resolution is being extended nationwide and worldwide, and thus lots of users are accustomed to an image of high resolution and high picture quality. Accordingly, a lot of institutes are giving impetus to the development of the next-image device. Furthermore, as there is a growing interest in Ultra High Definition (UHD) having resolution higher than HDTV along with HDTV, there is a need for compression technology for an image of higher resolution and higher picture quality.
For image compression, inter prediction technology for predicting a pixel value included in a current picture from an anterior picture or a posterior picture or both temporally, intra prediction technology for predicting a pixel value included in a current picture by using pixel information within a current picture, entropy coding technology for allocating a short sign to a symbol having a high frequency of appearance and allocating a long sign to a symbol having a low frequency of appearance, and so on may be used.